Davis — On the Fossil Fish of the Cretaceous Formations of Scandinavia. 377 



Ptychodus decurrens. 

 Ptychodus decurrens. 

 Ptychodus decurrens. 



Ptychodus depressus. 

 Ptychodus decurrens. 



Ptychodus decurrens. 



Ptychodus decurrens. 



Ptychodus polygyrus. 



Ptychodus decurrens. 



Ptychodus decurrens. 



Ptychodus latissimus. 



Ptychodus decurrens. 



Ptychodus decurrens. 



Ptychodus decurrens. 



Ptychodus decurrens. 



PiCTET, F. J., 1845. '' PaMontologie," vol. ii., p. 287. 

 GiEBEL, C. a, 1848. "Fauna der Vorwelt," p. 333. 

 Dixon, F., 1850. "Foss. Sussex," p. 302, pi. xxx., 



figs. 7, 8; pi. XXXI., fig. 1 ; pi. xxxii., fig. 5. 

 Dixon, F., 1850. " Foss. Sussex," p. 363, pi. xxxi., fig. 9. 

 Gervais, p., 1852. " Zool. et Pal. FranQ.," pi. lxxviii., 



fig. 5. 

 KiPRiJANOFF, v., 1852. "Bull. Soc. Imp. Nat. Moscou," 



vol. XXV., pt. ii., p. 490, pi. xiii., figs. 4,* 5. 

 QuENSTEDT, F. A., 1852. " Handb. Petrefakt.," p. 181, 



pi, XIII., fig. 59. 

 FiscHEK, C. E., 1856. " AUgem. deutsche naturh. Zeit. 



Dresden," N. S., vol. ii., p. 140, figs. 31-33. 

 Sauvage, H. E., 1872. " Biblioth. Ecole Hautes Etudes," 



vol. v., art. 9, p. 18. 

 Geinitz, H. B., 1875. " Palseontog.," vol. xx., pt. i., 



p. 296, pi. LXiv., figs. 24, 25. 

 St. Zarecznego, 1878. " Sprawozdanie Komisyi Fizy- 



jograf. Galicyi," vol. xii., p. 200, pi. viii., fig. 8. 

 Fritsch, a., 1878. "Reptil. u. Fische. bohm Kreide- 



form.,"p. 14, fig. 34. 

 Quenstedt, F. a., 1882. " Handb. Petrefakt.," 3rd ed., 



p, 281, woodcut, fig. 86, pi. xxi., figs. 63, 64. 

 Woodward, A. S., 1887. "Quart. Journ. Geol. Soc." 



vol. xliii., pp. 123-130, pi. x., figs. 1-10, 13. 

 Woodward, A. S., 1889. " Catal. Foss. Fishes Br. Mus.," 



p. 138. 



Represented by teeth from the soft white chalk of Annetorp and Oretorp in 

 the palseontological collection of the Riksmuseum at Stockholm. The larger 

 tooth is probably from the first lateral series of the upper jaw ;t it measures 

 0-02 m. across, and has a length antero-posteriorly of 0'017 m. ; nine ridges are 

 exposed, extending across the crown in nearly straight lines ; on each side they 

 bifurcate, and split up into a number of minute corrugations along the margins. 

 The nine ridges occupy an area of the surface of 0'012 m., the remaining portion 

 being covered with ramifying ridges increasing in number towards the margin. 

 The crown of the tooth is slightly convex. The root is buried in matrix. 



* A doubtful tooth, subsequently assigned to P. oweni, Kiprijanofl, he. cit., pt. ii., p. 2. 1881. 

 f See "Woodward's figures in Quart. Journ. Geol. Soc, vol, xliii., pi. x., fig. 4. 



